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Sign Up for FORCE NewslettersGenetic Testing for People Diagnosed with Colorectal Cancer
This section covers the following topics:
People with colorectal cancer should ask about genetic testing
Up to 10% of people diagnosed with colorectal cancer have an that caused their cancer. There are national guidelines that outline who should consider genetic counseling and testing for an linked to cancer. Speak with an expert about genetic testing for the following situations.
Guidelines for tumor testing followed by genetic testing
Experts recommend tumor testing all colorectal cancers to look for biomarkers known as "" () or microsatellite instability-High () at the time of diagnosis. These two related abnormalities are commonly found in the cancers of people with .
- People with dMMR/MSI-High cancers are recommended to have genetic counseling and testing for .
- dMMR/MSI-High cancers can occur in people who do not have . Not all people with cancers will test positive for a mutation.
- People with inherited mutations who develop colorectal cancer may have cancers that do not have these biomarkers.
- People with cancers that are not may still benefit from genetic counseling and testing.
- Cancers with these biomarkers tend to respond well to treatment with a certain type of treatment known as .
Guidelines for people with colorectal cancer and a history of
Genetic counseling and testing for an is also recommended for people diagnosed with colorectal cancer who have any of the following personal history of polyps:
- 10 or more of the adenomatous type
- 2 or more of the hamartomatous type
- 5 or more of the serrated type close to the rectum
Guidelines for people with colorectal cancer and a personal or family history of cancer
Genetic counseling and testing for an is also recommended for people diagnosed with colorectal cancer who have any of the following:
- a blood relative with a known in a colorectal cancer gene.
- diagnosed before age 50.
- diagnosed with another related cancer including endometrial, ovarian, pancreatic, stomach or other Lynch syndrome-related cancer.
- a close relative with a Lynch syndrome-related cancer diagnosed under age 50.
- two or more relatives with a Lynch syndrome-related cancer diagnosed at any age.
Other colorectal cancer survivors who may benefit from genetic counseling and testing
People with colorectal cancer may benefit from additional genetic counseling and expanded genetic testing if they had genetic testing in the past, tested negative, and:
- their situation matches any of the other guidelines above, and
- they had a test that only looked for one or a few genes, or
- they had genetic testing before 2014. Genetic testing has improved, and laboratories can now find gene mutations that may have previously been missed.
All colorectal cancer survivors and those in treatment should speak with a genetics expert to decide if genetic testing is right for them.
Genes linked to colorectal cancer
Mutations in the following genes have been linked to increased risk for colorectal cancer.
Syndrome (if applicable) |
Genes |
Notes |
Lynch syndrome |
Lynch syndrome is the most common inherited syndrome linked to colorectal cancer. People with Lynch syndrome who develop colorectal cancer are most likely to have tumors that are MSI-H or dMMR. People with Lynch syndrome have an increased risk for other types of cancers, too. |
|
Familial Adenomatous Polyposis (FAP) and Atypical Familial Adenomatous Polyposis (AFAP) |
People with FAP mutation may develop 100s of polyps and they may be diagnosed with colorectal cancer at a young age. People with FAP have an increased risk for other types of cancers. |
|
MUTYH Associated Polyposis (FMAP) |
People must have mutations in both copies of the MUTYH gene in order to develop this syndrome. People with MAP have an increased risk for other gastrointestinal tract cancers, too. |
|
PTEN Hamartoma Tumor syndrome |
People with PTEN Hamartoma Tumor syndrome have an increased risk for other types of cancers. |
|
Li-Fraumeni syndrome |
People with Li-Fraumeni syndrome have an increased risk for other types of cancer. |
|
Peutz-Jeghers syndrome |
Peutz-Jegher syndrome have an increased risk for other types of cancer. |
|
Multiple Endocrine Neoplasia 1 syndrome (MEN1) |
MEN1 |
MEN1 is linked to an increased risk for a type of tumor known as a neuroendocrine tumor. These tumors can occur in the gastrointestinal tract, including the colon. |
CHEK2 |
People with CHEK2 mutations have an increased risk for breast cancer, too. |
|
Other rare genes linked to colorectal cancer |
MSH3, NTHL1, AXIN2, GREM1, BMPR1A, SMAD4, POLE, POLD1 |